http ResponseWriter的CloseNotifier

i am using go 1.4.2 and the implementation doesn't seem to have CloseNotifier as i want to use it in a long polling handler with something like:

func Pollhandler(w http.ResponseWriter, r *http.Request) {

    notify := w.(CloseNotifier).CloseNotify()

    <-notify //should block until the http connection is closed

}

is the CloseNotifier not implemented for the http ResponseWriter? if so how can i get around this? or is there any implementation for http ResponseWriter that implements the CloseNotifier interface?

http.CloseNotifier has been there since Go 1.1. Your code doesn't work because you forgot the package part:

notify := w.(http.CloseNotifier).CloseNotify()